I'm gonna go the other way and say, if you're building a trail rig (specificly if you plan on hitting water), then go for some electric ones.
I run a set of Windstar fans on my K5. They replaced a non-clutch fixed blade fan. The biggest advantage I've found is that it warms up faster in the winter. Other than that, there isn't anything noteworthy about them. Didn't notice much, if any miliage increase. Throttle response seems a touch bit better though.
As far as being more dependable, if you've got the fans properly set up, you shouldn't have any problems. Hundreds of thousands of vehicles are on the road today with electric fans without any problems.